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Plylahan et al. Nanoscale Research Letters 2014, 9:544http://www.nanoscalereslett.com/content/9/1/544

NANO EXPRESS Open Access

Enhanced electrochemical performance ofLithium-ion batteries by conformal coating ofpolymer electrolyteNareerat Plylahan1,2, Sébastien Maria3, Trang NT Phan3, Manon Letiche1, Hervé Martinez4, Cécile Courrèges4,Philippe Knauth2 and Thierry Djenizian1,2*

Abstract

This work reports the conformal coating of poly(poly(ethylene glycol) methyl ether methacrylate) (P(MePEGMA))polymer electrolyte on highly organized titania nanotubes (TiO2nts) fabricated by electrochemical anodization of Ti foil.The conformal coating was achieved by electropolymerization using cyclic voltammetry technique. The characterizationof the polymer electrolyte by proton nuclear magnetic resonance (1H NMR) and size-exclusion chromatography (SEC)shows the formation of short polymer chains, mainly trimers. X-ray photoelectron spectroscopy (XPS) results confirmthe presence of the polymer and LiTFSI salt. The galvanostatic tests at 1C show that the performance of the half cellagainst metallic Li foil is improved by 33% when TiO2nts are conformally coated with the polymer electrolyte.

Keywords: Titania nanotubes; Polymer electrolyte; Electropolymerization; Lithium-ion batteries

BackgroundThe miniaturization of Lithium-ion batteries (LIBs) as apower source to drive small devices has been conti-nuously developed to meet the market requirements ofnomadic applications. The challenge of the minia-turization of LIBs is to minimize the size and, at thesame time, maximize the energy and power densities ofthe battery. In this context, 3D Li-ion microbatterieshave been developed to overcome this challenge.Particularly, nanoarchitectured electrodes such as self-organized titania nanotubes (TiO2nts) are a potentialcandidate as a negative electrode in 3D Li-ion microbat-teries [1-9]. TiO2nts show a better electrochemicalperformance compared to the planar TiO2 counterpart[6] due to i) their high active surface area, ii) the directcontact between the active material and the substrate,iii) fast diffusion of charges, and iv) high stability uponcycling owing to spaces between nanotubes, which allowthe volume variation caused by Li+ insertion/extraction.

* Correspondence: [email protected] Université, CNRS, LP3 UMR 7341, F-13288, Marseille Cedex 9,France2Aix-Marseille Université, CNRS, MADIREL UMR 7246, F-13397, Marseille Cedex20, FranceFull list of author information is available at the end of the article

© 2014 Plylahan et al.; licensee Springer. This isAttribution License (http://creativecommons.orin any medium, provided the original work is p

To achieve the fabrication of the full 3D Li-ion micro-batteries, the use of conventional organic liquid electro-lytes must be avoided due to the safety concerns and itsincompatibility to the integrated circuit technology. Poly(ethylene oxide) or poly(ethylene glycol) (PEG) is themost common polymer electrolyte used in LIBs due toits compatibility to the all-solid-state Li-ion microbat-teries [10], promising ionic conductivity [11,12], andthermal stability [13]. However, it is necessary to main-tain the 3D nanotubular structure of TiO2nts after thedeposition of the polymer electrolyte in order to sub-sequently fabricate the full 3D Li-ion microbatteries byfilling the polymer-coated TiO2nts with a cathode mate-rial. Recently, we have reported the electropolymerizationby cyclic voltammetry (CV) to conformally electrodepositthe PEG-based polymer electrolyte with bis(trifluoro-methanesulfone)imide or LiTFSI salt on the TiO2nts with-out closing the tube opening [14-16]. The conformalelectrodeposition of polymer is a convenient approach topreserve the 3D morphology of the substrate as it hasbeen reported for other materials [17]. The main advan-tage of the conformal coating is that all the active surfacearea of TiO2nts is in contact with the polymer electrolytes,which will improve the charge transport and thereby

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Plylahan et al. Nanoscale Research Letters 2014, 9:544 of 8http://www.nanoscalereslett.com/content/9/1/544

improving the performance of the microbatteries. It canbe noted that the electrochemical-assisted polymerizationprocess is a convenient and versatile approach. Indeed,the polymer formation can be achieved by different me-chanisms involving the formation of free-radical interme-diates, the activation by light, the use of initiator, andthe direct oxidation or reduction of monomer as it hasbeen reported for poly(para-phenylene)vinylene (PPV)[18], polypyrrole (PPy) [19], poly(2-methacryloyloxy(ethyl) acetoacetate) [20], and poly(sulfonated phenol)[21], respectively.In this work, we report the fabrication of highly ordered

and smooth TiO2nts and the conformal coating of thepolymer electrolyte: comb-shaped poly(poly(ethyleneglycol) methyl ether methacrylate) or P(MePEGMA) onTiO2nts by an electropolymerization technique. The mor-phology of the materials was characterized by scanningelectron microscopy (SEM) and transmission electronmicroscopy (TEM). The chemical structure of the obtainedP(MePEGMA) polymer was analyzed by proton nuclearmagnetic resonance (1H NMR) and its molar mass wasmeasured by size-exclusion chromatography (SEC). Thepolymer electrolyte was studied in depth by X-ray pho-toelectron spectroscopy (XPS). The electrochemical testswere carried out in the half cell to investigate the improvedperformance of the solid-state batteries caused by theconformal coating of TiO2nts with the polymer electrolyte.

MethodsTiO2nts were synthesized by electrochemical anodization[22] of Ti foil in an electrolyte containing 96.7 wt%glycerol, 1.3 wt% NH4F, and 2 wt% water. A constant volt-age of 60 V was applied to the cell (Ti foil as a workingelectrode and Pt foil as a counter electrode) for 3 h. Afterthe anodization, the sample was rinsed with deionizedwater without removing it from the cell.The electropolymerization on as-formed TiO2nts was

carried out by CV [14-16] in an aqueous electrolytecontaining 0.5 M LiTFSI and 0.2 M poly(ethylene glycol)methyl ether methacrylate or MePEGMA in a three-electrode system: TiO2nts as a working electrode, Pt foilas a counter electrode, and Ag/AgCl, 3 M KCl as a refe-rence electrode. MePEGMA is used as a starting mono-mer with an average molecular weight of 300 g mol−1 andan average repeating ethylene oxide unit of 5. Prior to theelectropolymerization, the electrolyte was purged with N2

for 10 min to remove dissolved oxygen. The CV was donefor five cycles in the three-electrode configuration at thescan rate of 10 mV/s, potential window of −0.35 to −1 Vvs Ag/AgCl, 3 M KCl. After the electropolymerization, thesample was dried without rinsing under vacuum at 60°Covernight.The morphology of TiO2nts and polymer-coated TiO2nts

were examined by electron microscopy techniques using a

JEOL 6320 F SEM and a JEOL 2010 F TEM (JEOL Ltd.,Akishima, Tokyo, Japan).

1H NMR spectra in CDCl3 were recorded on a BrukerAdvance 400 spectrometer (Bruker AXS, Inc., Madison,WI, USA). A chemical shift was given in parts permillion relative to tetramethylsilane. In order to cha-racterize the polymer by NMR, the sample was im-mersed during approximately 1 h in CDCl3. Then thesolution was recovered and concentrated to reach theminimum volume for an NMR analysis (≈0.5 mL).Polymer molecular weights and dispersities were

determined by SEC. The used system was an EcoSEC(Tosoh, Tokyo, Japan) equipped with a PL Resipore Pre-column (4.6 × 50 mm, Agilent Technologies, Inc., SantaClara, CA, USA) and two linear M columns (4.6 ×250 mm, Agilent) with a gel particle diameter of 3 μm.These columns were thermostated at 40°C. Detec-tion was made by an UV/visible detector operated atλ = 254 nm, a dual flow differential refractive indexdetector, both from Tosoh, and a viscometer ETA2010from PSS (Polymer Standards Service Inc., Amherst,MA, USA). Measurements were performed in THFat a flow rate of 0.3 mL min−1. Calibration was basedon polystyrene standards from Polymer Laboratories(ranging from 370 to 371,100 g mol−1).XPS measurements were performed on a Thermo

K-alpha spectrometer (Thermo Fisher Scientific, Waltham,MA, USA) with a hemispherical analyzer and a micro-focused monochromatized radiation (Al Kα, 1,486.7 eV) op-erating at 72 W under a residual pressure of 1 × 10−9 mbar.Peaks were recorded with a constant pass energy of 20 eV.The spectrometer was calibrated using the photoemissionlines of gold (Au 4f7/2 = 83.9 eV, with reference to theFermi level) and copper (Cu 2p3/2 = 932.5 eV). The Au4f7/2 full width at a half maximum (FWHM) was 0.86 eV.All samples were fixed on the sample holders in a glovebox directly connected to the introduction chamber of thespectrometer to avoid moisture/air exposure of thesamples. Charge effects were compensated by the use of acharge neutralization system (low-energy electrons) whichhas the unique ability to provide consistent charge com-pensation. Short acquisition time spectra were recordedbefore and after each experiment and compared, to checkthe non-degradation of the samples under the X-ray beam.The binding energy (BE) scale was calibrated from thehydrocarbon contamination using the C 1 s peak at285.0 eV. Core peaks were analyzed using a linear back-ground, except for the S 2p core peak for which a non-linear Shirley-type background was applied [23]. Thepeak positions and areas were obtained by a weightedleast-square fitting of model curves (using 70% Gaussianand 30% Lorentzian line shapes) to the experimentaldata. Quantification was performed on the basis ofScofield's relative sensitivity factors [24].


The electrochemical tests of bare TiO2nts and polymer-coated TiO2nts were carried out using galvanostaticmeasurements. TiO2nt electrodes were assembled againsta metallic Li foil using Swagelok cells in an Ar-filledglove box. Two sheets of Whatman paper soaked withMePEGMA+ LiTFSI electrolyte were used as a separator.The separators were prepared by soaking the circular disk(diameter of 10 mm) with an aqueous solution of 0.5 MLiTFSI + 0.8 M MePEGMA, then dried at 60°C in avacuum dryer overnight. The cells were cycled at 1C inthe potential window of 1.4 to 3 V vs Li/Li+ using VMP3(Biologic instrument).

Results and discussionThe morphology of as-formed TiO2nts and polymer-coated TiO2nts is shown in Figure 1. In Figure 1a,c, itcan be seen that highly organized TiO2nts are obtainedafter the anodization for 3 h. The top view (Figure 1a)shows the rounded shape of the tube opening with thediameter of approximately 100 nm and the wall thick-ness of 10 nm. The side view (Figure 1c) shows length ofthe tubes of approximately 1.5 μm. Figure 1b,d showsthe TiO2nts after the electropolymerization. The con-formal electrodeposition of the polymer electrolyte issupposed to occur according to a mechanism involvingthe formation of hydrogen free radicals as it is describedelsewhere [15,25]. The top view (Figure 1b) shows the

Figure 1 Morphology of as-formed TiO2nts and polymer-coated TiO2npolymer-coated TiO2nts, (c) cross section of as-formed TiO2nts, and (d) cro

thicker tube wall of approximately 20 nm which resultsfrom the deposition of the polymer. The side view(Figure 1d) shows that the spaces between tubes arefilled with the polymer.Figure 2 shows the TEM images of a single tube from

the polymer-coated TiO2nts sample. In Figure 2a, a thinlayer of polymer is clearly observed on the outer wall,from the top to the bottom of the tube. The enlargedview at the open end of the tube given in Figure 2bshows that the thickness of the conformal polymer layeris around 10 nm.After the conformal deposition of electrolyte on

TiO2nts has been achieved, the polymer electrolyte wasrecovered and characterized by 1H NMR to verify if thepolymer is formed and by SEC to estimate chain lengthof the polymer. The 1H NMR spectra of the MePEGMAmonomer and the P(MePEGMA) polymer are shown inFigure 3a,b, respectively. First, the polymer was success-fully extracted since the peak at 3.65 ppm correspondingto the methylene protons of the PEG chains togetherwith the peak at 3.40 ppm of the methyl ether end-chainare still present in the polymer spectrum. Moreover theelectropolymerization occurred since the peaks at 6.11and 5.58 ppm corresponding to the vinylic protons andthe singlet at 1.95 ppm of the methyl of the unsaturatedmethacrylic units in the monomer spectrum almost dis-appeared in the spectrum of the polymer (see arrows in

ts. SEM images of (a) top view of as-formed TiO2nts, (b) top view ofss -section of polymer-coated TiO2nts.

(a) (b)

Polymer

TiO2

Polymer

Polymer

TiO2

Figure 2 TEM images of a single tube from the polymer-coated TiO2nts sample. TEM images of (a) a single tube with conformal polymercoating and (b) enlarged view at the open end of the polymer-coated tube.


Figure 3). Additionally new peaks appeared in the poly-mer spectrum between 2.8 and 0.8 ppm, which are un-fortunately not easy to assign. This area of the spectrumshould contain peaks corresponding to the methyleneand methyl groups of the methacrylate backbone butalso some impurities. Indeed, considering the small vo-lume taken by the nanostructured polymer layer in thesample, the overall quantity of polymer available is verylow and it was difficult to avoid pollution of the

Figure 3 1H NMR spectra of (a) MePEGMA monomer and (b) P(MePEG

extracted material. For example, peaks at 0.88 and1.27 ppm could indicate the presence of linear alkanesand singlet at 1.6 ppm is due to water.The SEC chromatograms of P(MePEGMA) polymer

and MePEGMA monomer are shown in Figure 4. Thereare three evident peaks at the elution volume of 6.15,6.5, and 7 mL. It is noted that the average molecularweight of the monomer used in this work is approxi-mately 300 g mol−1. Hence, the peak at 6.5 mL is nearly

MA) polymer.

4,0 4,5 5,0 5,5 6,0 6,5 7,0 7,5

0,000

0,003

0,006

0,009

0,012

0,015

RI r

espo

nse

Elution volume (mL)

P(MePEGMA) MePEGMA

Figure 4 SEC chromatograms of P(MePEGMA) and MePEGMA.


superimposed to the peak corresponding to the mono-mer; this means that our electrolyte contains probablythe residual monomer, with modified end-chains con-sidering the NMR results. The peak at 6.15 mL showsthe highest intensity (800 g mol−1), which is three timesthe molecular weight of the monomer peak at 6.5 mL.Therefore, this peak can be assigned to trimers. Thepeak at 7 mL with the molecular weight of 154 g mol−1

is lower than the weight of the monomer. This peak maycorrespond to the broken side chain from the monomeror trimers. We also observe a very large shoulder bet-ween 5 and 6 mL indicating the formation of larger

Table 1 Binding energies (BE, eV), full width at a half maximumain components of TiO2nts coated with P(MePEGMA) and T

TiO2nts + P(MePEGMA)

BE (eV) FWHM (%) At.%

C 1 s 285 1.2 11.3

286.5 1.3 44.7

288 1.1 2.6

289.1 1.1 5.2

O 1 s 531 1.1 0.5

532.8 1.4 31

534 1.4 4.1

F 1 s 687.9 2.5 0.6

polymer species, but the signal intensity is too low to getmolar mass integration.XPS measurements were performed on self-organized

TiO2nts coated with P(MePEGMA) and TiO2nts coatedwith P(MePEGMA) + LiTFSI. All the quantitative data, in-cluding binding energies of the different species detected,full width at maximum height (FWMH) and atomic per-centages (At.%) are given in Table 1. For TiO2nts +P(MePEGMA) sample, O 1 s and C 1 s peaks are detected.These peaks mainly result from the oxygen and carbonatoms in the polymer. The F 1 s peak is attributed to theresidual fluoride ions from the anodization process since

m (FWHM, %), and atomic percentages (At.%) of theiO2nts coated with P(MePEGMA) + LiTFSI

TiO2nts + P(MePEGMA) + LiTFSI

BE (eV) FWHM (%) At.%

C 1 s 285 1.5 10

286.5 1.5 17.2

288 1.5 2.8

289.3 1.5 1.9

292.9 1.2 1.8

O 1 s 531.4 1.5 2.2

532.7 1.6 13.1

533.7 1.6 2.2

F 1 s 684.7 1.7 22.6

688.3 2.3 7

Li 1 s 55.9 1.4 15.1

N 1 s 399.6 2.1 1.7

S 2p 168.9 1.6 2.6

170.1 1.6


the anodization and the electropolymerization were car-ried out in the same electrochemical cell. For TiO2nts +P(MePEGMA) + LiTFSI sample, N 1 s, F 1 s, Li 1 s, and S2p peaks are detected in addition to O 1 s and C 1 s peaks,which results from the presence of LiTFSI salt [LiN(SO2CF3)2]. It can be noticed that no Ti and O atomsfrom TiO2nts have been observed in both samples, whichindicates that the corresponding nanotubes are completelycoated by the polymer electrolyte with a layer thicknessover 5 nm (≈depth analysis of XPS experiments), which isin agreement with the thickness determined by TEManalysis.The XPS spectra of C 1 s core peak for both samples are

presented in Figure 5 (for a non-exhaustive presentation,the other XPS spectra are not displayed). The C 1 s corepeak of TiO2nts + P(MePEGMA) (Figure 5a) presents fourmain components, which can be assigned to C-C andC-H at 285 eV, C-O at 286.5 eV, O-C-O at 288 eV, andO-C =O at 289.1 eV. The total concentration of C 1 s is63.9 At.%. The main component located at 286.5 eV (44.7At.%) corresponds to C-O bond in oligomer species ofPEG (−CH2-CH2-O-)n [26]. For C 1 s core peak ofTiO2nts + P(MePEGMA) + LiTFSI (Figure 5b), the foursimilar components are observed, plus an additionalcomponent at 292.9 eV (1.8 At.%), which can be assignedto CF3-like carbon atoms in LiTFSI (LiN(SO2CF3)2), aspreviously observed by Leroy et al. [27]. The total con-centration of C 1 s is 33.6 At.%. The O 1 s core peak ofTiO2nts + P(MePEGMA) sample is composed of two mainpeaks at 532.8 eV (31 At.%) and 534 eV (4.1 At.%), whichcorrespond to oxygen in PEG oligomer species. The totalconcentration of O 1 s is 35.5 At.%. The small componentat 531 eV (0.5 At.%) can be attributed to residual OHspecies on the surface. For TiO2nts + P(MePEGMA) +LiTFSI, three components can be assigned for O 1 s peak

294 292 290 288 286 284 282

Binding Energy (eV)

b) TiO2

nts+P(MePEGMA)+LiTFSI

a) TiO2nts+ P(MePEGMA)

Figure 5 C 1 s XPS spectra of TiO2nts coated with (a) P(MePEGMA)and (b) P(MePEGMA) + LiTFSI by electropolymerization.

at 531.2 eV (O-H, 2.2 At.%), 532.3 eV (13.1 At.%), and533.4 eV (2.2 At.%) (oxygen in PEG and LiTFSI). TheO-H bond observed in this sample may result from theadsorbed water by LiTFSI salt on the surface of thesample. The total concentration of O 1 s is 17.7 At.%. Itcan be noticed that the percentages of C 1 s (286.5 eV)and O 1 s (532.8 and 534 eV) components, relative toC-O (PEG), decrease from TiO2nts + P(MePEGMA) toTiO2nts + P(MePEGMA) + LiTFSI, which proves the pre-sence of the lithium salt at the surface of TiO2nts +P(MePEGMA). The presence of LiTFSI in TiO2nts + P(MePEGMA) + LiTFSI sample is confirmed by the XPSspectra of F 1 s (29.3% total atomic percentage), S 2p(2.6% total atomic percentage), Li 1 s (15.1% total atomicpercentage), and N 1 s (1.7% total atomic percentage). ForF 1 s spectrum, two components can be observed at684.7 eV (22.6 At.%), which may be assigned to LiF, and688.3 eV (7 At.%), which corresponds to F-C in LiTFSI.The component of LiF may result from the residual F¯from the anodization and Li+ from LiTFSI salt. It has to benoticed that the proportion between the C 1 s signal rela-tive to C-F (1.8 At.%) and the F 1 s signal of F-C (7 At.%) isin agreement with C-F3 ratio in LiTFSI. The peaks of Li 1 sand N 1 s are located at 55.9 eV and 399.6 eV, respectively,and the S 2p signal is composed of S 2p1/2 at 168.9 eV andS 2p3/2 at 170.1 eV. These results are in agreement withprevious XPS core peak characterization of LiTFSI done byLeroy et al. [27] and Plylahan et al. [14].To summarize, our results show that self-organized

TiO2nts are successfully coated with the polymer electro-lyte, and the presence of PEG and LiTFSI is confirmed.The positive effect of the conformal coating of the

polymer electrolyte on the electrochemical performanceof the nanotubes was investigated by galvanostatic tests.Bare TiO2nts and polymer-coated TiO2nts were testedin a half cell against a metallic Li foil using separator

0 10 20 30 400

25

50

75

100

125

150

175

Spe

cific

cap

acity

(m

A h

g-1)

Cycle number

Bare TiO2tns

Polymer-coated TiO2nts

Figure 6 Specific capacity vs cycle number of bare TiO2nts andpolymer-coated TiO2nts at 1C between 1.4 to 3 V vs Li/Li+.


soaked with 0.5 M LiTFSI + 0.8 M MePEGMA. The cyc-ling performance at 1C in the potential window between1.4 and 3 V vs Li/Li+ is shown in Figure 6. The polymer-coated TiO2nts deliver an average reversible capacity of100 mA h g−1 which is improved by 33% as compared tobare TiO2nts (approximately 75 mA h g−1). The betterperformance is attributed to the conformal coating ofthe polymer electrolyte that increases the contact areabetween electrode and electrolyte. This increased con-tact leads to a better Li+ transport and thereby impro-ving the performance of the battery. The irreversiblecapacity at the first cycle is a normal behavior observedfor anatase and amorphous TiO2nts [6,9,10,16]. Thisirreversible capacity is caused by the side reaction oflithium ions and residual water in the polymer andadsorbed surface water on TiO2nts. Also, some lithiumions are trapped inside the lattice after the first insertion(first discharge). The capacity fading is fairly low as aresult of the 3D nanotubular structure that allows thevolume variation during cycling.

ConclusionsThe highly conformal electrodeposition of P(MePEGMA)polymer electrolyte on highly organized TiO2nts has beenachieved using the cyclic voltammetry technique. Thecharacterization of the polymer electrolyte by 1H NMRand SEC shows the formation of short polymer chains,mainly trimers and some traces of high molar mass poly-mer species as well as MePEGMA monomers. The indepth studies of polymer-coated TiO2nts by XPS confirmthe presence of polymer and LiTFSI salt. The electro-chemical tests of TiO2nts in the half cell against metallicLi foil show the improved performance of the LIBs by 33%at 1C when TiO2nts are conformally coated with the poly-mer electrolyte.

Competing interestsThe authors declare that they have no competing interests.

Authors’ contributionsNP and ML prepared the samples. NP conducted the electrochemical testsand prepared the manuscript. SM and TP conducted 1H NMR and SECexperiments and prepared the manuscript. HM and CC conducted the XPSmeasurements and prepared the manuscript. PK and TD supervised thestudy. All the authors read and approved the final manuscript.

AcknowledgementsWe acknowledge the Région PACA and ANR JCJC no. 2010 910 01 forfinancial supports.

Author details1Aix-Marseille Université, CNRS, LP3 UMR 7341, F-13288, Marseille Cedex 9,France. 2Aix-Marseille Université, CNRS, MADIREL UMR 7246, F-13397,Marseille Cedex 20, France. 3Aix-Marseille Université, CNRS, ICR UMR 7273,F-13397, Marseille Cedex 20, France. 4IPREM-ECP-UMR 5254, Université dePau et des Pays de l’Adour, Hélioparc Pau-Pyrénées, 2 Av du Président Angot,64053, Pau Cedex 9, France.

Received: 16 May 2014 Accepted: 16 September 2014Published: 2 October 2014

References1. Ellis BL, Knauth P, Djenizian T: Three-dimensional self-supported metal

oxides for advanced energy storage. Adv Mater 2014, 26:3368–3397.2. Fang D, Huang K, Liu S, Li Z: Electrochemical properties of ordered TiO2

nanotube loaded with Ag nano-particles for lithium anode material.J Alloys Compd 2008, 464:L5–L9.

3. Kyeremateng NA, Lebouin C, Knauth P, Djenizian T: The electrochemicalbehaviour of TiO2 nanotubes with Co3O4 or NiO submicron particles:composite anode materials for Li-ion micro batteries. Electrochim Acta2012, 88:814–820.

4. Wei W, Oltean G, Tai C-W, Edström K, Björefors F, Nyholm L: Highenergy and power density TiO2 nanotube electrodes for 3D Li-ionmicrobatteries. J Mater Chem A 2013, 1:8160.

5. Djenizian T, Hanzu I, Knauth P: Nanostructured negative electrodes basedon titania for Li-ion microbatteries. J Mater Chem 2011, 21:9925.

6. Ortiz GF, Hanzu I, Djenizian T, Lavela P, Tirado L, Knauth P: AlternativeLi-ion battery electrode based on self-organized titania nanotubes.Chem Mater 2009, 21:63–67.

7. Kyeremateng NA, Plylahan N, dos Santos ACS, Taveira LV, Dick LFP,Djenizian T: Sulfidated TiO2 nanotubes: a potential 3D cathode materialfor Li-ion micro batteries. Chem Commun 2013, 49:4205–4207.

8. Kyeremateng NA, Vacandio F, Sougrati M-T, Martinez H, Jumas J-C, KnauthP, Djenizian T: Effect of Sn-doping on the electrochemical behaviour ofTiO2 nanotubes as potential negative electrode materials for 3D Li-ionmicro batteries. J Power Sources 2013, 224:269–277.

9. Ortiz GF, Hanzu I, Knauth P, Lavela P, Tirado JL, Djenizian T: TiO2 nanotubesmanufactured by anodization of Ti thin films for on-chip Li-ion 2Dmicrobatteries. Electrochim Acta 2009, 54:4262–4268.

10. Plylahan N, Letiche M, Barr MKS, Djenizian T: All-solid-state lithium-ionbatteries based on self-supported titania nanotubes. ElectrochemCommun 2014, 43:121–124.

11. Agrawal RC, Pandey GP: Solid polymer electrolytes: materials designingand all-solid-state battery applications: an overview. J Phys D Appl Phys2008, 41:223001.

12. Song JY, Wang YY, Wan CC: Review of gel-type polymer electrolytes forlithium-ion batteries. J Power Sources 1999, 77:183–197.

13. Bernhard R, Latini A, Panero S, Scrosati B, Hassoun J: Poly(ethylenglycol)dimethylether–lithium bis(trifluoromethanesulfonyl)imide, PEG500DME–LiTFSI, as high viscosity electrolyte for lithium ion batteries. J PowerSources 2013, 226:329–333.

14. Plylahan N, Kyeremateng NA, Eyraud M, Dumur F, Martinez H, Santinacci L,Knauth P, Djenizian T: Highly conformal electrodeposition of copolymerelectrolytes into titania nanotubes for 3D Li-ion batteries. Nanoscale ResLett 2012, 7:349.

15. Kyeremateng NA, Dumur F, Knauth P, Pecquenard B, Djenizian T:Electrodeposited copolymer electrolyte into nanostructured titaniaelectrodes for 3D Li-ion microbatteries. C R Chim 2013, 16:80–88.

16. Kyeremateng NA, Dumur F, Knauth P, Pecquenard B, Djenizian T:Electropolymerization of copolymer electrolyte into titania nanotubeelectrodes for high-performance 3D microbatteries. Electrochem Commun2011, 13:894–897.

17. Mazzotta E, Surdo S, Malitesta C, Barillaro G: High-aspect-ratio conductingpolymer microtube synthesis by light-activated electropolymerization onmicrostructured silicon. Electrochem Commun 2013, 35:12.

18. Djenizian T, Gelloz B, Dumur F, Chassigneux C, Jin L, Koshida N: Directelectropolymerization of poly(para-phenylene)vinylene films on Si andporous Si. J Electrochem Soc 2010, 157:H534–H539.

19. Surdo S, Strambini LM, Malitesta C, Mazzotta E, Barillaro G: Highly conformalgrowth of microstructured polypyrrole films by electrosynthesis onmicromachined silicon substrates. Electrochem Commun 2012, 14:1–4.

20. Agarwal R, Bell J: Electropolymerization of 2-methacryloyloxy(ethyl)acetoacetate on aluminum using a novel initiation method. J Appl PolymSci 1999, 71:1665–1675.

21. Hou H, Vacandio F, Vona ML, Di Knauth P: Electropolymerization ofsulfonated phenol by cyclic voltammetry. J Appl Polym Sci 2013,129:1151–1156.

22. Kowalski D, Kim D, Schmuki P: TiO2 nanotubes, nanochannels andmesosponge: self-organized formation and applications. Nano Today2013, 8:235–264.

23. Shirley DA: High-resolution X-ray photoemission spectrum of the valancebands of gold. Phys Rev 1972, B5:4709.


24. Scofield JH: Hartree-slater subshell photoionization cross-sections at 1254and 1487 eV. Electron Spectrosc Relat Phenom 1976, 8:129–137.

25. Cram S, Spinks G, Wallace G, Brown H: Mechanism ofelectropolymerisation of methyl methacrylate and glycidyl acrylate onstainless steel. Electrochim Acta 2002, 47:1935–1948.

26. Leroy S, Blanchard F, Dedryère R, Martinez H, Carre B, Lemordant D,Gonbeau D: Surface film formation on a graphite electrode in Li-ionbatteries: AFM and XPS study. Surf Interface Anal 2005, 37:773–781.

27. Leroy S, Martinez H, Dedryvère R, Lemordant D, Gonbeau D: Influence ofthe lithium salt nature over the surface film formation on a graphiteelectrode in Li-ion batteries: an XPS study. Appl Surf Sci 2007,253:4895–4905.

doi:10.1186/1556-276X-9-544Cite this article as: Plylahan et al.: Enhanced electrochemicalperformance of Lithium-ion batteries by conformal coating of polymerelectrolyte. Nanoscale Research Letters 2014 9:544.

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